The impact of two organic contaminations on the damage characteristics of anti-reflector (AR) at 1064 nm is investigated. Contamination experiments were made with toluene and acetone in liquid phase on the surface of AR coatings. Chemical and morphological characterization methods were used to identify and understand the damage process. The possible damage process is analyzed and discussed. It is found that toluene decreases laser-induced damage threshold and acetone seems to be benign and has little influence on laser-induced damage threshold due to its quickly spreading into the coating. Adsorption and droplet micro-lensing effect mechanism are the main cause of enhanced laser-induced damage of toluene. (C) 2009 Elsevier B. V. All rights reserved.